US20100115901A1 - Lawn mower having collecting and mulching modes - Google Patents

Abstract

A walk behind lawn mower has an exit tunnel that is opened and closed by a pivotal mulch door to convert the mower between collecting and mulching modes of operation. An operating handle fixed to the mulch door includes a vertically reciprocal push button for releasing locking tabs that engage detents for holding the mulch door in the open and closed positions thereof. The bottom wall of the exit tunnel has a steeply inclined rear ramp section that is angled upwardly relative to the horizontal at least approximately 45°. The rear discharge opening of the exit tunnel occupies approximately an upper quarter of the area of the rear face of the cutting deck. Grass clippings flow into the upper portion of a grass collector through this high, steeply angled exit tunnel to promote even and full filling of the grass collector in the collecting mode.

Description

TECHNICAL FIELD
• This invention relates generally to walk behind rotary lawn mowers that are selectively convertible by the user between collecting and mulching modes of operation.
BACKGROUND OF THE INVENTION
• Walk behind lawn mowers are well known for mowing grass. Such mowers comprise a movable cutting deck having a cutting chamber that carries a substantially horizontal rotary cutting blade. A handle extends upwardly and rearwardly from deck the deck. An operator grips the handle and walks behind the mower to guide and control the mower.
• The cutting chamber is formed on the underside of deck4 and includes a top wall and a downwardly extending, peripheral side wall. The cutting chamber has an open bottom facing the ground so that the blade rotating inside the cutting chamber can contact and sever grass as the cutting chamber moves over the ground. The cutting chamber is often shaped as an annular channel extending around most of the periphery of the cutting chamber adjacent the sidewall of the cutting chamber. The grass clippings created by the blade will circulate through at least a portion of this annular channel before leaving the cutting chamber through an exit tunnel.
• The exit tunnel receives the grass clippings from the cutting chamber and conducts the grass clippings to a rear discharge opening on the exit tunnel. The grass clippings are often collected in a grass collector when such a collector is connected to the discharge opening. This is the collecting mode of operation of the lawn mower. Alternatively, the rear discharge opening of the exit tunnel can be selectively closed by a pivotal mulch door to retain the grass clippings within the cutting chamber for downward discharge into the cut grass path. This is the mulching mode of operation of the lawn mower. U.S. Pat. No. 7,367,174, assigned to the assignee of this invention, discloses a lawn mower that is selectively convertible by the user between collecting and mulching modes of operation through the use of a pivotal mulch door in the exit tunnel.
• While mowers having pivotal mulch doors are known, the mulch doors are often operated by linkages that are fairly complicated and obtrusive. Many of these linkages are often contained on the exterior of the mower and include numerous parts. This leads to extra expense in manufacturing the mower and decreases the aesthetics of the mower. There is a need in the art for a mulch door that can be operated by a simple and durable mechanism that is largely hidden within the mower. The operating mechanism should be conveniently located and easy to operate by the user. The operating mechanism desirably should also securely lock or retain the mulch door in the open or closed positions thereof.
• In addition, the performance of the mower in both its collecting and mulching modes should be optimized to the maximum extent possible despite the presence of the mulch door. Often, mowers that are convertible between collecting and mulching modes might work well in one mode but not the other, i.e. they might be a good mulching mower but a poor grass collecting mower or vise versa. Accordingly, there is also a need for a mower of this type which has excellent performance in both modes of operation.
SUMMARY OF THE INVENTION
• One aspect of this invention relates to a lawn mower having at least a collecting mode of operation. The mower comprises a cutting deck having a downwardly facing cutting chamber. A handle assembly extends upwardly and rearwardly from the cutting deck to allow a user who walks behind the cutting deck to guide and operate the cutting deck. A rotatable cutting blade within the cutting chamber cuts grass by rotating about a substantially vertical axis of rotation within a substantially horizontal cutting plane. An exit tunnel located on the deck extends rearwardly from a front inlet opening to a rear discharge opening located on a rear face of the deck. A grass collector for receiving and retaining grass clippings has an open mouth substantially overlying the rear face of the deck and completely overlying the rear discharge opening of the exit tunnel. The grass collector extends rearwardly from the cutting deck. The exit tunnel has a bottom wall that includes a rear ramp section having a rear edge that forms a lower edge of the rear discharge opening. The rear ramp section is inclined approximately at least 45° upwardly relative to the horizontal for projecting the grass clippings upwardly into an upper portion of the grass collector.
• One aspect of this invention relates to a lawn mower having at least a collecting mode of operation. The mower comprises a cutting deck having a downwardly facing cutting chamber. A handle assembly extends upwardly and rearwardly from the cutting deck to allow a user who walks behind the cutting deck to guide and operate the cutting deck. A rotatable cutting blade within the cutting chamber cuts grass by rotating about a substantially vertical axis of rotation within a substantially horizontal cutting plane. An exit tunnel located on the deck extends rearwardly from a front inlet opening to a rear discharge opening located on a rear face of the deck, wherein the rear face has an upper left quarter, an upper right quarter, a lower left quarter and a lower right quarter from a perspective of an observer standing behind the rear face and looking forwardly. A grass collector receives and retains grass clippings therein. The grass collector has an open mouth that substantially covers all four quarters of the rear face and extends rearwardly from the cutting deck. The rear discharge opening of the exit tunnel has an open area that covers approximately one of the upper quarters of the rear face.
• Yet another aspect of this invention relates to a lawn mower convertible between mulching and collecting modes of operation. The mower comprises a cutting deck which is supported by rotatable ground engaging members for movement over the ground. A downwardly facing cutting chamber defined by the deck has a top wall, a peripheral substantially circular sidewall extending vertically downwardly from the top wall, and an open bottom circumscribed by the sidewall. A rotatable cutting blade within the cutting chamber for cuts grass by rotating about a substantially vertical axis of rotation within a substantially horizontal cutting plane. An exit tunnel located on the deck extends rearwardly from a front inlet opening to a rear discharge opening. The front inlet opening is positioned in the circular sidewall of the cutting chamber at one side of a rear of the cutting chamber and the rear discharge opening is positioned behind the front inlet opening and the cutting chamber. A pivotal mulch door within the exit tunnel is selectively pivotal by a user between an open position and a closed position relative to the exit tunnel about a substantially horizontal axis located adjacent an upper edge of the front inlet opening of the exit tunnel. The mulch door in the open position permits grass clippings to pass through the exit tunnel and into a grass collector associated with the rear discharge opening of the exit tunnel in the collecting mode of operation. The mulch door in the closed position prevents grass clippings from passing through the exit tunnel such that the grass clippings must eventually leave the cutting chamber through the open bottom of the cutting chamber in the mulching mode of operation. An operating handle is fixedly connected to the mulch door for pivoting the mulch door between its open and closed positions. The handle extends from the mulch door through an elongated fore and aft extending slot leading into an interior portion of the deck with the slot having front and rear ends. The mulch door is in the open position thereof when the handle is positioned at one end of the slot and the mulch door is in the closed position thereof when the handle is positioned at the other end of the slot.
BRIEF DESCRIPTION OF THE DRAWINGS
• This invention will be described more completely in the following Detailed Description, when taken in conjunction with the following drawings, in which like reference numerals refer to like elements throughout.
• FIG. 1 is a perspective view of a lawn mower according to this invention, particularly illustrating the mower without a grass collector;
• FIG. 2 is a perspective view of the mower ofFIG. 1, particularly illustrating the mower with a grass collector separated from the rear of the mower;
• FIG. 3 is a perspective view similar toFIG. 2, particularly illustrating the mower with a grass collector attached to the rear of the mower;
• FIG. 4 is a perspective view of the mower ofFIG. 1, particularly showing a rear cover in a lowered position covering the rear discharge opening of the exit tunnel;
• FIG. 5 is a perspective view similar toFIG. 4, but showing the rear cover having been separated from the rear of the mower;
• FIG. 6 is an enlarged perspective view of the rear of the mower as shown inFIG. 5, particularly illustrating a removable battery having been removed from a battery compartment through the rear face of the mower and illustrating the pivotal mulch door in its installed position within the mower with the mulch door being closed in the exit tunnel to place the mower into the mulching mode of operation;
• FIG. 7 is a perspective view similar toFIG. 6, but showing the pivotal mulch door also having been removed from the mower and positioned behind the mower;
• FIG. 8 is a perspective view of a portion of the mower ofFIG. 1 with a portion of the sidewall of the cutting chamber having been removed, particularly illustrating the handle of the mulch door in a rear position corresponding to the closed position of the mulch door in the mulching mode of operation;
• FIG. 9 is a perspective view similar toFIG. 8, but showing the handle in a front position corresponding to an open position of the mulch door in the collecting mode of operation;
• FIG. 10 is a partial cross-sectional view of the handle of the mulch door as shown inFIG. 9, particularly illustrating the push button of the handle and its engagement with a front detent for holding the handle in the front position;
• FIG. 11 is a partial cross-sectional view similar toFIG. 10, but with the handle having been removed to show the curved rail forming the front and rear detents for holding the handle in the front and rear positions thereof, respectively;
• FIG. 12 is a partial cross-sectional view similar toFIG. 10, particularly illustrating only the push button of the handle and its engagement with the rear detent for holding the handle in its rear position;
• FIG. 13 is a partial, longitudinal cross-sectional view of the rear of the mower ofFIG. 1 taken through the exit tunnel, particularly illustrating the mulch door in a closed position in the exit tunnel to place the mower into its mulching mode of operation;
• FIG. 14 is a cross-sectional view similar toFIG. 13, but now showing a grass collector having been attached to the rear of the mower and with the mulch door in an open position in the exit tunnel to place the mower into its collecting mode of operation;
• FIG. 15 is a transverse cross-sectional view of the mower as shown inFIG. 1 taken through the rear of the cutting chamber just forward of the front inlet opening of the exit tunnel, particularly illustrating the exit tunnel from the front thereof;
• FIG. 16 is a cross-sectional view similar toFIG. 15, but with the shroud that covers the mulch door and battery having been removed to illustrate both the mulch door and the battery from the front thereof;
• FIG. 17 is a top plan view of the bottom of the exit tunnel and the curved rear scroll that forms the rear portion of the sidewall of the cutting chamber; and
• FIG. 18 is a longitudinal cross-sectional view through the exit tunnel and sidewall portion depicted inFIG. 17, particularly illustrating the steeply inclined rear ramp of the exit tunnel.
DETAILED DESCRIPTION
• A walk behind lawn mower according to this invention is generally illustrated as2 inFIG. 1.Mower2 includes a cutting deck4 supported for rolling over the ground by fourwheels6 at the corners of deck4. Short ground engaging rollers could be substituted for eachwheel6 or long rollers spanning the width of deck4 could be substituted for each pair ofwheels6 or both pairs ofwheels6 if so desired. The center of deck4 has a slight depression or indentation in which aninternal combustion engine8 is mounted. Other power sources, such as an electric motor, fuel cell, hybrid gas-electric power system, etc., could be used in place ofengine8.Engine8 has a vertical drive spindle (not shown) that extends down through the top wall of deck4.
• An upwardly and rearwardly extendinghandle assembly9 allows an operator to walk behindmower2 to guide and operatemower2. In a self-propelled version of mower, handleassembly9 can include aslidable handle grip11 for controlling the ground speed ofmower2.Slidable handle grip11 is disclosed in more detail in U.S. Pat. No. 6,982,083, which is hereby incorporated by reference.
• Arotary cutting blade10 is mounted on the vertical spindle ofengine8 beneath the top wall of deck4 to rotate in a substantially horizontal cutting plane. Deck4 includes an annular cutting chamber extending around deck4 with the cutting chamber being bounded by an outer, circumferentialperipheral sidewall12 extending downwardly from atop wall13 of the cutting chamber. As cuttingblade10 is rotated in its horizontal cutting place, sharpened cutting edges at the tips of cuttingblade10 sever the grass and create grass clippings. The tips of cuttingblade10 have trailing upturned sails that create a circumferential airflow. Thus, the grass clippings are circulated within the annular cutting chamber in the direction of the arrows A inFIG. 1 which corresponds to the direction in which the blade is rotated.
• How the grass clippings exit from the cutting chamber depends upon whethermower2 is in a collecting or a mulching mode of operation. In the collecting mode as shown inFIG. 3, agrass collector14 having anopen mouth15 is attached to the rear ofmower2. Theopen mouth15 ofgrass collector14 can be seen inFIG. 2. In addition as shown inFIG. 13, anexit tunnel16 on top of deck4 at the right rear end ofmower2 is open to provide a passageway through the rear ofmower2. Thus, the grass clippings after being cut flow in the direction of the arrows A and then exit directly throughexit tunnel16 during their first pass through the cutting chamber to be deposited within and collected bygrass collector14.
• In the mulching mode,grass collector14 may be present as shown inFIG. 3 or may be removed as shown inFIG. 1. Regardless of whether or notgrass collector14 is present,exit tunnel16 is selectively closed by the user ofmower2. Now, the grass clippings cannot leave the cutting chamber throughexit tunnel16 but are circulated around the cutting chamber in the direction of the arrows A. This recirculation might last for a number of passes around the cutting chamber until the grass clippings are cut and recut and eventually fall downwardly into the cut grass path through the open bottom face of the cutting chamber. In the mulching mode, these grass clippings, which have been driven downwardly into and largely hidden by the remaining standing grass in the cut grass path, will decompose and serve as nutrients to the turf.
• Referring now toFIGS. 4-7, the rear ofmower2 has a generally planarrear face18 that is inclined slightly forwardly as it rises. A pivotalrear cover20 has a pair oftrunnions22 extending to either side thereof as best shown inFIG. 5.Trunnions22 pivotally mount cover20 in short,circular hubs21 or openings onsupport flanges23 along the upper edge ofrear face18 ofmower2. SeeFIG. 9. This avoids the expense of an elongated, transverse pivot rod for journalingcover20 sincetrunnions22 can be molded as part ofcover20. Preferably, cover20 is a one piece molded plastic part having a raisedcenter channel24 and aside flap26 on either side ofchannel24. Thelower edge28 ofchannel24 forms a hand grip for allowing a user to manually raisecover20
• Cover20 rotates about a substantially horizontal pivot axis x1 from a lowered position in which side flaps26 ofcover20 abut againstrear face18 ofmower2, as shown inFIG. 4, to a raised position in which cover20 overlies and rests atop the front ofgrass collector14, as shown inFIG. 3. Two torsion springs30, best shown inFIG. 6, act betweencover20 and some other portion ofmower2 to biascover20 in the direction of the arrow B inFIGS. 4 and 5. Thus, cover20 is normally disposed in its lowered position with side flaps26 abutting againstrear face18 ofmower2 along theirlower edges27.Cover20 stands off or is spaced away fromrear face18 ofmower2 as illustrated by the gap g inFIG. 13. The user can insert his or her hand into the gap g and griplower edge28 ofchannel24 to manually raisecover20 against the bias of torsion springs30. This is done when attachinggrass collector14 tomower2 or to otherwise gain access torear face18 ofmower2.
• One reason for gaining access torear face18 ofmower2 is to remove or install abattery32 that is carried onmower2.Battery32 could have different purposes onmower2. In a simple system,battery32 is simply a source of electrical power used for startingengine8 whenengine8 is equipped with an electric starter. In a more complex system,battery32 could also comprise a source of electrical power for powering an electric motor(s) used either for rotatingcutting blade10 or for wheel drive propulsion or both. In this latter use,battery32 could be part of a battery only drive system or be part of an engine/battery hybrid drive system.
• Regardless of the use ofbattery32 on a particular mower, abattery compartment34 is provided that is substantially enclosed within the body ofmower2. As best shown inFIG. 6,battery compartment34 is accessed through an access opening36 provided inrear face18 ofmower2.Battery compartment34 includes a substantiallyhorizontal floor38 which receives a slidable tray orcradle40.Battery32 is dropped down intocradle40 and is retained incradle40 by a short, upwardly projectinglip42 extending around the front and sides ofcradle40.
• The rear ofcradle40 includes an upwardly extendingrear wall44 that extends abovebattery32 such that theupper edge46 of the rear wall is exposed. Thisedge46 forms a grip for allowing the user to slidecradle40 into or out ofbattery compartment34. Whencradle40 has been inserted into the compartment,cradle40 is secured in place by abolt48 that passes through arear flange50 ofcradle40 and is tightened down into a threadedboss52 formed on a ledge ofrear face18 immediately below the access opening tobattery compartment34. Suitableelectrical connectors54 are provided inbattery compartment34 for connectingbattery32 to whatever system onmower2 uses the electrical power stored inbattery32.
• This structure provides an easy method for servicing or replacingbattery32 if need be. The user can raisebattery32 cover, unscrewbolt48, grab the grip provided byupper edge46 of the rear wall ofcradle40, and then simply slidecradle40 andbattery32 out ofmower2 throughrear face18 ofmower2. Theelectrical connectors54 can be disconnected either prior to or aftercradle40 is slid out. This slide in and slide outcradle40 eases the task of battery maintenance and is user friendly. In addition,battery32 is conveniently hidden within the body ofmower2 during use, but is easily removable frommower2 without having to disassemble any parts ofmower2. All the user has to do is pivotcover20 upwardly, unscrewcradle40, and pullbattery32 out by slidingcradle40 out. No substantial numbers of additional parts are required sincecover20 is needed in any event for abutting againstrear face18 ofmower2 to close offexit tunnel16 whengrass collector14 is not attached tomower2.
• Referring further toFIG. 6, the rear discharge opening56 ofexit tunnel16 is depicted to the right of access opening36 tobattery compartment34. Rear discharge opening56 is located inrear face18 ofmower2. InFIG. 6, the viewer is looking intoexit tunnel16 through rear discharge opening56 towards the front inlet opening58 ofexit tunnel16. However, front inlet opening58 ofexit tunnel16 is blocked inFIG. 6 by apivotal mulch door60, which is shown in the closed position thereof.
• As is also seen inFIG. 6, rear discharge opening56 ofexit tunnel16 has a height h and a width w that define an open area. This open area is approximately 25 to 35% of the area ofrear face18 ofmower2. Moreover, rear discharge opening56 ofexit tunnel16 occupies one of the upper quarters ofrear face18 ofmower2. Thelower edge57 of rear discharge opening56 is also approximately half way up the height ofrear face18 ofmower2. The significance of this positioning will be described in more detail hereafter.
• InFIG. 7,mulch door60 has been removed from the interior ofmower2 and pulled out. Now, the viewer can look all the way throughexit tunnel16 and down into the interior of the cutting chamber.Mulch door60 and a lower portion of anoperating handle62 formulch door60 are molded together out of plastic as a single piece.Mulch door60 has acylindrical hub64 formed therewith. The ends ofcylindrical hub64 pivotallyjournal mulch door60 incircular openings66 in walls in ashroud68 that is part of the body ofmower2. As shown inFIG. 7, the rear ofmulch door60 has a plurality of strengtheningribs69. The front ofmulch door60, hidden inFIG. 7 but visible inFIG. 8, is smooth.
• Referring now toFIGS. 8-12, theaforementioned shroud68 in whichmulch door60 is pivoted is seen inFIG. 8 from the front.Shroud68 has an elongated fore andaft slot70 through which handle62 extends whenmulch door60 is in place inexit tunnel16. The lower portion ofhandle62 has anenlarged knob72 secured to the top thereof.FIG. 8 depicts handle62 in a raised rear position thereof corresponding to the closed position ofmulch door60. Note thatmulch door60 can be seen inFIG. 8 having been swung down into engagement with the bottom ofexit tunnel16 to close or block off front inlet opening58 to exittunnel16 substantially immediately behindfront inlet opening58. In achieving this pivoting motion,mulch door60 pivots about the substantially horizontal pivot axis defined by the axis ofhub64. This pivot axis is labeled x2 inFIG. 8.
• Referring now toFIG. 9, to openexit tunnel16, namely to pivotmulch door60 upwardly towards the top ofexit tunnel16, the user must grabknob72 ofhandle62 and must push handle62 downwardly from the upper rear end ofslot70 into engagement with the lower front end ofslot70. When this occurs,mulch door60 is swung up insideexit tunnel16 until it folds up generally adjacent the top wall ofexit tunnel16. Notemulch door60 is no longer visible inFIG. 9 since it has moved up out of view in this lowered position ofhandle62. In this position ofhandle62,mower2 is in the collecting mode and the grass clippings can exit the cutting chamber and move intograss collector14 by passing through the nowopen exit tunnel16.
• Preferably, a retainer is provided for locking or holdingmulch door60 in its open or closed positions. One embodiment of such a retainer is illustrated herein. That embodiment includes adepressible push button74 carried on top ofhandle62 within the enlarged knob. As shown inFIG. 9, the push button has a dog bone or barbell shape received inside a similarly shaped cavity inknob72. The user can push down onpush button74 in the direction of the arrow C inFIG. 10 with the user's thumb or palm as the user gripsknob72 with his or her hand.
• Referring further toFIG. 10,push button74 has an extendedslide76 that passes down through the lower portion ofhandle62. Each side ofslide76 includes alocking tab78 formed thereon with only onesuch locking tab78 being visible inFIG. 10 as lockingtab78 on the other side ofslide76 is hidden. Each side ofslot70 has acurved rail80 on an underside ofshroud68adjacent slot70 with the ends ofcurved rail80 forming both an upper rear detent82rand a lower front detent82f.SeeFIG. 11 for an illustration of front andrear detents82.
• Acompression spring84 is provided beneathslide76 ofpush button74.Spring84 extends between the bottom ofslide76 and the top ofhub64 ofmulch door60.Spring84 can be partially seen inFIG. 10.Spring84 biases pushbutton74 upwardly relative to handle62 in the direction of the arrow D inFIG. 10. Thus, the top ofpush button74 has a normal position in which it is extended a small distance above the surface ofknob72 ofhandle62, as best shown inFIGS. 9 and 10.
• InFIG. 10, handle62 is shown locked in its lower front position. Lockingtabs78 onslide76 ofpush button74 are located in the lower front detents82fon either side ofslot70. To releasehandle62 for movement, the user simply grips handle62 and pushes down onpush button74 with his or her thumb or palm to depress lockingtabs78 against the bias ofspring84 until lockingtabs78 have cleared the front detents82f.The operator then simply pivots handle62 up the length ofslot70 untilhandle62 engages against the upper rear end ofslot70. At this point, the operator can release handle62 andpush button74 simply by removing his or her hand fromhandle62. The bias ofspring84 will then causeslide76 to rise to engage lockingtabs78 with the upper rear detents82rwithspring84 biasing also causingpush button74 to pop back out of the top ofknob72. SeeFIG. 12. Thus,mulch door60 can be moved between its open and closed positions, and can be retained in either of its open and closed positions, by a simple, intuitively operable operating handle62 that is merely slid from one end of a fore andaft slot70 to another to select either of the two desired positions and that has a simple release provided bypush button74.
• Referring now toFIGS. 15-18, the rear portion of the cutting chamber is formed by anarcuate scroll86 having avertical face88.Scroll86 is individually depicted inFIG. 17.Scroll86 is secured within a metal casting that forms much of the rest of deck4. When in place, thevertical face88 ofscroll86 forms a continuation of that portion of the circumferential,peripheral sidewall12 of the annular cutting chamber provided in the metal casting. Thus, as shown inFIG. 15, the tip of cuttingblade10 sweeps past thissidewall12, i.e. sweeps past thevertical face88 ofscroll86, as it rotates around within the cutting chamber. A bottom half ofexit tunnel16 is formed as part ofscroll86 as shown inFIGS. 17 and 18. The top half ofexit tunnel16 is formed as part ofshroud68.
• The bottom half ofexit tunnel16 formed inscroll86 has an upwardly facing U-shaped defined by abottom wall90 ofexit tunnel16 and bylower sections92 of spaced side walls ofexit tunnel16.Bottom wall90 ofexit tunnel16 includes three separate sections, namely anentrance section94 at the beginning ofexit tunnel16 immediately in back of front inlet opening58, a curved or arcuatemiddle transition section96, and a rather steeply inclinedrear ramp section98. SeeFIG. 18.Rear ramp section98 is steeply angled upwardly relative to horizontal, as indicated by the angle αFIG. 18, in the range of 45° to 60° and preferably approximately 52° to 57°, with the end ofrear ramp section98 comprising thelower edge57 of rear discharge opening56 ofexit tunnel16. In addition, the total rise onbottom wall90 ofexit tunnel16 from the lower edge59 of front inlet opening58 to thelower edge57 of rear discharge opening56 is approximately equal to the length ofexit tunnel16. This configuration effectively locates rear discharge opening56 ofexit tunnel16 quite high onrear face18 ofmower2 as seen inFIG. 6.
• The high location of rear discharge opening56 ofexit tunnel16 in conjunction with the steeply inclinedrear ramp section98 ofbottom wall90 ofexit tunnel16 directs the grass clippings fromexit tunnel16 into the front ofgrass collector14 in a direction against the front of the top wall ofgrass collector14. This is shown by the arrows E inFIG. 14. This optimizes the performance ofmower2 in its collecting mode. Grass clippings are deposited intograss collector14 in a manner that most efficiently loads the grass clippings intograss collector14 without such clippings dribbling back out ofexit tunnel16.
• Theentire exit tunnel16 is shown in longitudinal cross-section inFIGS. 13-15. This includes the bottom half ofexit tunnel16 formed byscroll86 shown inFIGS. 18 and 19. The remainder ofexit tunnel16, namely the top half ofexit tunnel16 comprising theupper sections100 of the side walls and thetop wall102 ofexit tunnel16, is formed inshroud68 that forms part of the body ofmower2. Together, these two pieces, namely scroll86 andshroud68, form thecomplete exit tunnel16. In addition,shroud68 serves to pivotallyjournal mulch door60 inopenings66 and includesslot70 in which handle62 ofmulch door60 moves.Shroud68 is simply bolted to the top wall of the metal deck casting by a plurality ofbolts104 shown inFIG. 16.
• Referring now specifically toFIG. 13,mulch door60 is shown in its closed position. In this position,mulch door60 inclines downwardly and slightly rearwardly from its pivot axis at the front ofexit tunnel16 wheretop wall102 ofexit tunnel16 begins to rise in height relative to the top of deck4. The free rear end ofmulch door60 engagesbottom wall90 ofexit tunnel16 generally along the line or junction betweenentrance section94 andmiddle transition section96. As shown inFIG. 13, this blocksexit tunnel16 to the passage of grass clippings throughexit tunnel16 and placesmower2 into its mulching mode of operation.
• Ifmulch door60 is pivoted into its open position withoutgrass collector14 being attached to the rear ofmower2, cover20 will remain closed due to the bias of torsion springs30. Thus, the user and bystanders are still protected against the passage of thrown objects or the like due to the presence ofcover20 even though the user might inadvertently leavemulch door60 in the open position. However, cover20 stands off fromrear face18 ofmower2 as shown by the gap g inFIG. 13.
• Thus, if the user operatesmower2 withgrass collector14 removed andmulch door60 inadvertently left open, the grass clippings can pass through the gap g. These grass clippings will be directed downwardly towards the ground bycover20 and will be deposited on the ground in back ofmower2. This serves to alert the user thatmulch door60 is still open. The user can then pivotmulch door60 to its closed position to seal offexit tunnel16 to the passage of any grass clippings.
• FIG. 14 shows the orientation ofmulch door60 whenmulch door60 is open andgrass collector14 is attached, i.e.mower2 is in the collecting mode. In this position,mulch door60 has been folded up againsttop wall102 ofexit tunnel16.Mulch door60 is only slightly less inclined than the steeply inclinedrear ramp section98 ofbottom wall90 ofexit tunnel16, i.e.mulch door60 in its open position is approximately parallel torear ramp section98. As shown inFIG. 14 by the arrows E, the stream of grass clippings will be thrown in a direction that causes the stream to impact against the top wall ofgrass collector14 in the front half ofgrass collector14. Again, as noted earlier, the Applicants have found that this orientation and the size and placement of rear discharge opening56 relative to the open mouth ofgrass collector14, namely rear discharge opening56 is about 25 to 35% of the area of the open mouth ofgrass collector14 and is positioned in an upper quarter ofgrass collector14, to be effective in causing even and full filling ofgrass collector14. Thus, performance as a grass collecting lawn mower has been optimized.
• Yet, in the mulching mode, performance is also very good.Mulch door60 hangs down and pivots from a front end ofexit tunnel16 to seal offexit tunnel16 substantially at or slightly behind front inlet opening58 to exittunnel16. Essentially, whenmulch door60 is in place, there is little disruption in the normal annular shape of the cutting chamber. This aids in mulching sinceexit tunnel16 will not fill or pack with grass clippings sinceexit tunnel16 is closed off at front inlet opening58 rather thanrear discharge opening56.
• Various modifications of this invention will be apparent to those skilled in the art. For example, the slide in-slide out mounting ofbattery32 in an access opening34 inrear face18 ofmower2, whichopening34 is normally closed off bycover20, could be used in mowers other than those incorporatingexit tunnel16 andmulch door60.
• In addition,mower2 could be provided with other than the above described collecting and mulching modes of operation. For example,sidewall12 of the cutting chamber could be provided with a selectively openable side discharge opening (not shown) for discharging grass clippings to one side ofmower2. In addition, instead of usinggrass collector14, a rear discharge chute could be mated with rear discharge opening56 for discharging grass clippings to the rear ofmower2. Thus, the scope of the invention shall be limited only by the appended claims.

Claims (20)

1. A lawn mower having at least a collecting mode of operation, which comprises:

(a) a cutting deck having a downwardly facing cutting chamber;

(b) a handle assembly extending upwardly and rearwardly from the cutting deck to allow a user who walks behind the cutting deck to guide and operate the cutting deck;

(c) a rotatable cutting blade within the cutting chamber for cutting grass, wherein the cutting blade rotates about a substantially vertical axis of rotation within a substantially horizontal cutting plane;

(d) an exit tunnel located on the deck, wherein the exit tunnel extends rearwardly from a front inlet opening to a rear discharge opening located on a rear face of the deck;

(e) a grass collector for receiving and retaining grass clippings therein, the grass collector having an open mouth substantially overlying the rear face of the deck and completely overlying the rear discharge opening of the exit tunnel, wherein the grass collector extends rearwardly from the cutting deck; and

(f) wherein the exit tunnel has a bottom wall that includes a rear ramp section having a rear edge that forms a lower edge of the rear discharge opening, wherein the rear ramp section is inclined approximately at least 45° upwardly relative to the horizontal for projecting the grass clippings upwardly into an upper portion of the grass collector.

2. The lawn mower ofclaim 1, wherein the rear discharge opening has an open area that covers approximately at least 25% of that portion of the rear face covered by the open mouth of the grass collector.

3. The lawn mower ofclaim 1, wherein the rear face has an upper left quarter, an upper right quarter, a lower left quarter and a lower right quarter from a perspective of an observer standing behind the rear face and looking forwardly, wherein the open mouth of the grass collector substantially covers all four quarters of the rear face, and wherein the rear discharge opening has an open area that covers approximately one of the upper quarters of the rear face.

4. The lawn mower ofclaim 3, wherein the upper quarter covered by the open area of the rear discharge opening is on that side of the rear face that the blade rotates towards given a predetermined direction of blade rotation.

5. The lawn mower ofclaim 4, wherein the blade rotates in a clockwise direction from a perspective of an observer standing behind the rear face and looking forwardly and downwardly, and wherein the wherein the upper quarter covered by the open area of the rear discharge opening is the upper right quarter of the rear face.

6. The lawn mower ofclaim 1, wherein the lawn mower also has a mulching mode of operation, and further including a pivotal mulch door in the exit tunnel that pivots between a closed position to block the flow of grass clippings through the exit tunnel in the mulching mode of operation and an open position to permit the flow of grass clippings through the exit tunnel and into the grass collector in the collecting mode of operation.

7. The lawn mower ofclaim 6, wherein the mulch door pivots about a substantially horizontal pivot axis at an upper edge of the front inlet opening to the exit tunnel.

8. A lawn mower having at least a collecting mode of operation, which comprises:

(a) a cutting deck having a downwardly facing cutting chamber;

(b) a handle assembly extending upwardly and rearwardly from the cutting deck to allow a user who walks behind the cutting deck to guide and operate the cutting deck;

(c) a rotatable cutting blade within the cutting chamber for cutting grass, wherein the cutting blade rotates about a substantially vertical axis of rotation within a substantially horizontal cutting plane;

(d) an exit tunnel located on the deck, wherein the exit tunnel extends rearwardly from a front inlet opening to a rear discharge opening located on a rear face of the deck, wherein the rear face has an upper left quarter, an upper right quarter, a lower left quarter and a lower right quarter from a perspective of an observer standing behind the rear face and looking forwardly;

(e) a grass collector for receiving and retaining grass clippings therein, the grass collector having an open mouth that substantially covers all four quarters of the rear face, wherein the grass collector extends rearwardly from the cutting deck; and

(f) wherein the rear discharge opening has an open area that covers approximately one of the upper quarters of the rear face.

9. The lawn mower ofclaim 8, wherein the upper quarter covered by the open area of the rear discharge opening is on that side of the rear face that the blade rotates towards given a predetermined direction of blade rotation.

10. The lawn mower ofclaim 8, further including a pivotal rear cover pivotally attached adjacent an upper edge of the rear face, wherein the rear cover is spring biased to abut against a portion of the rear face when the grass collector is removed to overlie the rear discharge opening of the exit tunnel when the grass collector is removed.

11. The lawn mower ofclaim 10, wherein the lawn mower also has a mulching mode of operation, and further including a pivotal mulch door in the exit tunnel that pivots between a closed position to block the flow of grass clippings through the exit tunnel in the mulching mode of operation and an open position to permit the flow of grass clippings through the exit tunnel and into the grass collector in the collecting mode of operation.

12. The lawn mower ofclaim 11, wherein the rear cover has a portion that overlies but stands off a portion of the rear discharge opening such that grass clippings can flow through the exit tunnel if the mulch door is in the open position thereof and pass out of the exit tunnel against the rear cover, and wherein the rear cover is shaped to deflect such exiting grass clippings downwardly onto the ground behind the cutting deck to alert the operator to the fact that the mulch door is in the open position.

13. The lawn mower of claim of10, further including a battery compartment in an interior of the cutting deck with the battery compartment being reached by an access opening thereto provided in the rear face, wherein the access opening to the battery compartment is made accessible when the rear cover is pivoted upwardly by a user relative to the rear face.

14. The lawn mower ofclaim 13, wherein the access opening to the battery compartment is located in the other upper quarter of the rear face.

15. A lawn mower convertible between mulching and collecting modes of operation, which comprises:

(a) a cutting deck which is supported by rotatable ground engaging members for movement over the ground;

(b) a downwardly facing cutting chamber defined by the deck, the cutting chamber having a top wall, a peripheral substantially circular sidewall extending vertically downwardly from the top wall, and an open bottom circumscribed by the sidewall;

(c) a rotatable cutting blade within the cutting chamber for cutting grass, wherein the cutting blade rotates about a substantially vertical axis of rotation within a substantially horizontal cutting plane;

(d) an exit tunnel located on the deck, wherein the exit tunnel extends rearwardly from a front inlet opening to a rear discharge opening, wherein the front inlet opening is positioned in the circular sidewall of the cutting chamber at one side of a rear of the cutting chamber and the rear discharge opening is positioned behind the front inlet opening and the cutting chamber;

(e) a pivotal mulch door located within the exit tunnel, wherein the mulch door is selectively pivotal by a user between an open position and a closed position relative to the exit tunnel about a substantially horizontal axis located adjacent an upper edge of the front inlet opening of the exit tunnel, wherein the mulch door in the open position permits grass clippings to pass through the exit tunnel and into a grass collector associated with the rear discharge opening of the exit tunnel in the collecting mode of operation, and wherein the mulch door in the closed position prevents grass clippings from passing through the exit tunnel such that the grass clippings must eventually leave the cutting chamber through the open bottom of the cutting chamber in the mulching mode of operation; and

(f) an operating handle fixedly connected to the mulch door for pivoting the mulch door between its open and closed positions, wherein the handle extends from the mulch door through an elongated fore and aft extending slot leading into an interior portion of the deck with the slot having front and rear ends, wherein the mulch door is in the open position thereof when the handle is positioned at one end of the slot and the mulch door is in the closed position thereof when the handle is positioned at the other end of the slot.

16. The mower ofclaim 15, wherein the handle includes an enlarged upper knob that the user may grasp with the user's hand, and further including a push button that is biased by a spring to normally extend above the knob to be engageable by a hand of the user when the user grips the knob, the push button being depressible by the user to release a detent engagement that holds the handle in one of the two positions thereof.

17. The mower ofclaim 16, wherein the push button is part of a slide that vertically reciprocates relative to the handle, the slide having at least one locking tab engageable with one of a pair of detents located on one side of the slot in which the handle pivots.

18. The mower ofclaim 17 wherein one detent locates and retains the handle at one end of the slot and the other detent locates and retains the handle at the other end of the slot.

19. The mower ofclaim 17, wherein the slide of the push button includes a pair of locking tabs on opposite sides thereof, and wherein two pairs of detents are located on opposite sides of the slot to cooperate with the pair of tabs, one tab cooperating with each pair of detents.

20. The mower ofclaim 17, wherein the mulch door, a lower portion of the handle, and a cylindrical hub that pivotally mounts the mulch door rotate together as a unit, wherein the slide of the push button is carried within the lower portion of the handle, and wherein the spring that biases the slide of the push button is located between an underside of the slide and the top of the cylindrical hub of the mulch door.

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